Friction device for brakes and clutches.



PATBNTED FEB. 6, 1906.

C. W. HUNT. FRIGTION DEVICE FOR BRAKES AND CLUTGHBS.

AIPLIOATIDH FILED TURB 14, 1805.

2 SHEETS-SHEET 1.

PATENTED FEB. 6, 1906.

G. W. HUNT.

FRIGTIN DEVICE POR. BRAKES AND CLUTCHES.

APPLIOATION FLEI) 31111314, 1905.

B SHEETS-SHEET 3.

UNITED sfrATnsv4 PATENT OFFICE.

CHARLES WALLACE HUNT, OF W EST NEW BRIGHTUN, NEW YORK.

FRICTION DEVICE FOR BRAKES AND CLUTCHES.

Specification of Letters Patent.

Patented Feb. 6, 1906.

Application led June 14, 1906. Serial No. 265,142.

To @ZZ whom it inlay concern:

Be it known that I, CHARLES WALLACE IIUNT, a citizen of the United States, residing in West New Brighton, borough of Richmond, city of New York, State of New York, have invented certain new and useful Improvements in Friction Devices Jfor Brakes and Clutches, of which thefollowing isa specification, reference being had to the accompanying drawings, forming a part hereof.

The object of this invention is to rovide an improved friction device for bra es and clutches which shall operate with great power,

. section, showing the application of t although requiring comparatively slight movement of the actuating part and the op- A eration of which shall be assisted by the rela tive movement of the parts.

The embodiments of the invention which have been chosen for iilustration and expla nation herein are designed with especialrefcrence to the application of the invention in the operation of hoisting-drums, and in one case the invention is shown as embodied in a brake which is intended to be applied antoinatically when the drum is rotated backward under the stress of the load in order to prevent the backward rotation of the driving-motor, and in the other case it is shown as embodied in a clutch which is intended to control the hoisting-drum.

The invention will be more fully described hereinafter with reference to the accompanying drawings, in which it is illustrated, and in which- Figure 1 is a view in elevation, partly in e invention to a brake to prevent backward rotation of the driving-shaft under the stress of the load. Fig. 2 is a view, partly in elevation and partly in section, on the irreguiar piane indicated by the line 2 2 of Fig. 1. Fig. 3 is a partial section on the plane indicated by the line 3 3 of Fig. 1. Fig. 4 is a view simiiar to Fig. 1, but illustrating the application of the invention to a clutch which is appiied directly to a hoisting-drain. Fig. 5 is a view, partly in side elevation and partl in section, on the irregular piane indicated7 by the iine 5 5 of Fi 4, the hoistin -drurn being shown in part. gFig. 6 is a detai view, partly in section, showing in part the brake-actuatin mechanism.

n the embodiment of the invention illustrated in Figs. 1, 2, and 3 a driving-shaft is represented at a, and the shaft to be driven therefrom is indicated at b. To the drivingshaft is secured a driving-arm c, the end or ends of which are suitably formed to coperate with a driven arm d, secured to the driven shaft or member l), so that the driven shaft or member shall be driven positively when the driving -shaft or member is rotated contra clockwise. Secured to a suitable support, such as the pedestal e, is a stationary friction member f, shown in the present instance as an Ordinar flanged brakedrnm. The second mem er of the friction device, in this case the movable member, is shown as an ordinary brake-band g, arranged to cooperate with the stationary friction member f. In accordance with the present invention the two ends of the brake or friction band are arranged to be moved by devices hereinafter described in the same direction, but diiierentiall so that when the device is being ciosed oth ends oi the brake-band are` moved in the same direction, contra-clockwise in the drawings, but with such relative speeds that the brake-band is caused to bug tightly the xed friction member, and when the device is being opened both ends of the band are moved in the same direction, clockwise, but at different speeds, so that the brake-band is freed from the sta tiener friction member. In the construction s own one end g of the brake-band is carried by a lever h, which is pvoted at i upon the arm d. The other end g2 of the brake-band is carried by a lever k, which is pivoted at lupon the arm d. The two levers are aiso connected at their opposite ends, as by a link m. The pivots fi and l of the two levers are so positioned with respect to each other, or, in other words, the two levers h and lc are so proportioned, that the movement of the end g of the brake-band g shali be considerably greater than the movement of the end g2, the two arms of the lever h being in this instance substantially equal, while the two arms of the lever lc are unequal, being a proximateiy in the ratio of four to one.

onscquently the movement of the end g of the brak -band is approximately four times greater than the corresponding movement of the end g. The lever h in thisform of the invention is preferablysnbjected to the action of a sprmgfor the purpose of insuring light frictionai contact between the band g and the drumf, and it is therefore provided with an extension k to bear u on a spring n, which is supported by a stop on the arm d. The arm c 1s also preferably provided with a IOO IIO

projection c to cooperate under certain conditions with a lateral projection h2 of the extension h. In the operation of this embodiment of the invention it will be assumed that the driving-shaft ay is rotated contra-clockwise. It therefore through the cooperation of the arms c and d carries the shaft b in the same direction. The movement of the arm d carries the pivots i and l of the levers h and l? in the same direction, dragging the brakeband over the brake-drum. As the drag of the end g of the band is greater than that of the end g2 of the band, the band is expanded relatively to the brake-drum, and is therefore released from effective contact with the brake-drum. If now the stress of the load tends to rotate the shaft b in the opposite direction, it may be desirable, especially if the shaft a be driven by an electric motor, to prevent backward rotation of the shafts a and b. A slight backward rotation of the shaft b, carryin With it the arm d, moves the pivots i and slightly in a clockwise direction in res ect to the stationary friction member j.

hrough the slight frictional contact of the brake-band with the drum, as hereinbefore explained, the pivot Q1 of the lever L is moved slightly with respect to the end g of the band, and the latter is therefore caused to hug the brake-drum still more tightly, since the corresponding movement of the end g2 of the brake-band is much less. The power of application of the brake is therefore proportioned to the force which tends to rotate the shaft b in the opposite direction, and all of the parts are therefore held firmly against rotation in the opposite direction. However, if the driving-motor is reversed then the projection c of the arm c strikes the lateral projection h2 of the extension h of the lever z, compresses the spring n, and moves the levers h and 7c upon their pivots, so as to move both ends of the brake-band toward the right hand in Fig. 1. Since the movement lof the end g is much greater than the end gz, as already explained, the brake-band is expanded and the brake released.

In the embodiment of the invention illustrated in Figs. 4, 5, and 6 the drum o, which is to be driven through the improved friction device, is re resented as mounted loosely upon the driving-shaft p. To the latter is secured to rotate therewith a spider g, which in the operation of the improved device serves the purposes of the arm d of the construction shown 1n Figs. 1, 2, and 3, furnishing the pivotal supports i and lfor the levers h and c, which haveconnected thereto at their outer ends, respectivel the ends of the frictionstrap g, and on t e other side of their fulcr'a are connected by the link m. The frictionstrap g in this instance coperates with a frictlon-drum f on the hoisting-drum o. In this case ards r are shown as secured to the spider g or the purpose of limiting the outl ward movement of the friction-strap g. As will be readily understood, a slight movement of the lever h upon its fulcrunl produces a corresponding movement of the end g of the friction-strap in one direction and a much smaller movement of the end o2 of the friction-strap in the opposite direction, so that the friction-strap is quickly released from operative engagement with the friction-drum or is caused to hug the same with great force, as the case may be. If the shaft p and the s ider g be rotated in a direction contrac ockwise, tending to move the pivot i of the lever h away from the end g of the frictionstrap, the tendency of the movement will be to disengage the strap from operative contact with the drum; but if the shaft and spider be rotated in a clockwise direction, so that the pivot i of the lever h tends to move forward of the end of the lever to which the end g of the friction-strap is attached, the tendency of the movement will be to cause the friction strap to hug the drum more closely, and thereby increase the driving engagement.

The means which are provided for the operation of the clutch at will may be of any suitable construction. As shown in Figs. 4, 5, and 6 of the drawings, the inner end of the lever h is connected by a link s with a collar t, which is movable longitudinally on the shaft p, but is compelled to rotate therewith. The collar t is engaged in turn by a collar u, which does not rotate, but can be moved longitudinally by suitable means, such as the screws o, which are carried by the stationary frame w.

Whether the improved friction device be applied to a brake or to a clutch and Whether it be embodied in the particular structure shown and described herein or in other equivalent structures, it will be seen that it acts with great power and yet requires but slight movement of the operating part to bring it into action and to secure the power desired. It will be evident, moreover, that various changes may be made in the details of construction and arrangement without departing from the spirit of the invention.

I claim as my invention- 1. A friction device for brakes and clutches, comprising a friction-band, a friction-surface to cooperate with said band, differential levers independent and substantially radial to which the ends of said band are respectively secured and means to move both of said levers in one direction or the other, whereby the ends of said band are moved differentially in one direction or the other.

2. A friction device for brakes and clutches, comprising a friction-band, a friction-surface to coperate with said band, differential levers independent and substantially radial to which the ends of said band are respectively secured, a support for said levers, said support and said friction-surface being rela- IIO tively movable, and means to move said levers in one direction or the other.

3. A friction device for brakes and cutches, comprising a friction-band, a friction-surface to cooperate with said band, differential levers independent and substantiallyY radial to which the ends of said band are respectively secured, a support for said levers, a connection between said levers, and ineens to actnate said levers.

4. A friction device for brakes and clutches comprising a friction-band, a friction-surface to cooperate with said band, two substantially radial levers pivoted at points between their ends and having res ectively unequal arms, the ends ofthe band Yein respectively secured to the outer ends of said evers, acominon support for said levers, a link connecting the inner arms of said levers at different distances from the pivots respectively, and means to actuate said levers.

5. A friction device, comprising a frictionband, a stationaryT friction-surface to coop* erate with said band, a driving part, a driven part, and differential levers mounted on said driven part and having the ends of said band connected thereto respectively.

6. A friction device, comprising a friction band,`a stationarjyT friction-surface to coperatewith said brake, a driving part, a driven part, dilerential levers mounted on said driven part and having the ends of said band connected thereto respectively, and a link connecting said levers.

7. A friction device, comprising a frictionband, a stationary friction-surface to copcrate with said brake, a driving part, a driven part, differential levers mounted on said driven part and having the ends of said band connected therewith respectively, and a spring operating on one of said levers to maintain frictional contact between said band and said friction-surf ace.

8. A friction device, comprising a frictionband, a stationaqT friction-surface to coperate with said brake, a driving part, a driven part, and differential levers mounted on said driven part and having the ends of said band connected thereto respectively, said driving part being adapted to engage one of said levers in backward movement.

This specification signed and witnessed this 12th day of June, A. D. 1905.

CHARLES WALLACE HUNT.

in presence of- WILLIAM D. Srrvnns, CHAs. E. SIMoNsoN. 

